Alkyl ethoxy carboxylate surfactants are typically prepared from alkyl polyether nonionic surfactants. Specifically, the alkyl ethoxy carboxylate surfactants are formed by first reacting ethoxylated fatty alcohol with a hydroxide base to deprotonate the alcohol and form the corresponding alkoxide base. The alkoxide is then reacted with a salt of chloroacetic acid to produce the alkyl ethoxy carboxylate. However, the chloroacetic acid salt also has a tendency to react with the hydroxide base in an unwanted side reaction to form a glycolate salt. In order to obtain high conversion of the ethoxylated alcohol to the alkyl ethoxy carboxylate, the reaction must be run at elevated temperature and under reduced pressure so as to drive the equilibrium of the deprotonating reaction toward the alkoxide base and avoid the unwanted side reaction. Alternatively, the reaction may be run using excess hydroxide base and excess chloroacetic acid and subsequently removing the contaminant that is formed by the hydroxide and the chloroacetic acid salt.
It is an object of this invention to provide a process for producing alkyl ethoxy carboxylate surfactants using a selective hindered base in place of a hydroxide base in order to avoid unwanted side reactions and eliminate the need to remove unwanted contaminants.
It is a further object of this invention to provide a process for producing alkyl ethoxy carboxylate surfactants so that a minimal amount of anhydrous chloroacetic acid or a salt thereof is used in converting the ethoxylated alcohol into the alkyl ethoxy carboxylate product.